Bee clustering has been a common sight to all beekeepers, during spring and summer months. Sometimes, a substantial portion if not nearly all of the front face of the beehive may be covered with bees, with a cluster which may be about one inch thick. Indeed, even the bottom entrance to the hive may be covered. In such circumstances, as many as several pounds of bees may particiate in clustering, and the cluster may stay in place on the front of the beehive for several days. When a cluster occurs, this is indicative of a stressed or abnormal condition within the beehive, and one of its dangers--apart from decreased honey production--is that of swarming.
H. L. Wallace, U.S. Pat. No. 3,927,431, issued Dec. 23, 1975, teaches a ventilating spacer for beehives, which comprises a frame member which is intended to be installed over the top-most honey super and which comprises openings on two sides of the frame member. The principal reason for the provision of the ventilating spacer, according to Wallace, is to ventilate the hives so much that the formation of queen cells is suppressed and therefore that the natural tendency of bees to swarm is essentially negated. In other words, according to Wallace, a swarm, if it can be captured, is not a difficult problem to re-hive, although it is a great nuisance; but he is concerned that swarming occurs during honey flow or sometime previous to the main honey flow, but can be reduced by providing excessive ventilation which, he suggests, suppresses the tendency of the bees to build a number of queen cells as a preliminary step to swarming.
I have discovered that clustering of bees, which may or may not lead to swarming, in any event may be precluded in several different manners. One way, also suggested by Wallace,(above), is by staggering the brood chambers by one-quarter or three-eighths (0.25 to 0.375) inches, which creates slots in the front and back of the hive. This, however, creates several other problems including the necessity for additional bees to guard against robber bees from other hives, the increased likelihood that wax moths may enter the hive, and most particularly the fact that during cool nights and in cool weather the hives lose too much heat, thereby requiring that the bees consume more honey to generate the additional heat being lost.
As noted, bee clustering may lead to swarming, and has been suggested in some publications as being a consequence of excessive heat within a hive.
Following considerable observations and study, I have determined the following:
1. Bees cluster only on strong hives. Weak hives do not cluster;
2. Bee clustering takes place when the ambient air temperature is about 60.degree. F. and higher.
3. Clustering seems to occur irrespective of the location of the hive. Clustering may occur whether the hive is in the sun, or in the shade.
4. Clustering occurs predominantly when the ambient air is moist, having a high relative humidity (usually 80% R.H., or more).
5. I have found that, if the top cover of a beehive is lifted at the front by, say, one fourth (0.25) inch and is supported to leave that opening, the cluster within the hive will disappear within one to three hours.
6. Clustering occurs generally when nectar is available, and usually not otherwise.
7. All of the bees at the bottom entrance to the beehive, which are visible from the outside, and which are fanning their wings, are facing the hive. In such a position, those bees can only drive the air out of the hive.
8. Hives which have been propylized heavily, exhibit a higher frequency of clustering and clustering may be of longer duration.
9. After the spring or early summer inspection of the bees by the beekeeper, the bees are not in any hurry to re-propylize the beehive, particularly at the interface between the underside of the top board or cover of the beehive, and the top-most honey super.
From the above observations, I have arrived at the following thesis, which has led to the development of the honey drying ventilator for beehives, according to the present application.
It appears that the real cause or reason for clustering in beehives is not, as previously suggested, a tendency to swarm or excess heat within the beehive; the clustering occurs because there is an inadequate air supply to dry the nectar which has been collected by the bees. The average quality nectar contains about 27% sugars, and 73% water; whereas, honey contains approximately 81% sugars and about 19% water. Thus, it takes approximately three pounds of nectar from which two pounds of water must be evaporated to produce one pound of honey. On the average, I estimate that there will be about 5,000 cubic feet of ambient air required to move through the hive, in order to evaporate two pounds of water and thus to produce one pound of honey. A detailed discussion occurs hereafter.
In order to move air through the beehive, the bees fan their wings at the bottom bee entrance, and by doing so they create a partial vacuum within the hive. As a result, air enters the hive through unpropylized interfaces and cracks between the supers, and also between the top-most super and the underside of the top board. When an insufficient amount of air enters the hive, as many bees as may be required move out of the hive and cluster on the front wall thereof, so that the remaining bees within the hive can better circulate the air within the hive. When an adequate opening is provided at the top of the hive, then enough air will enter the hive and the bee cluster on the front face thereof disperses, and bees can then go about their normal business of collecting more nectar for the production of more honey.
I have discovered, by careful observation of the air flow at the top and bottom of a beehive during the honey season, that when honey is drying the air enters the beehive through the upper opening if one is provided, or through the unpropylized cracks as discussed above, and that moisture laden air is discharged from the hive through the bottom entrance. When the bees stop the honey drying process--i.e., when the bees facing the bottom entrance to the hive stop fanning their wings--normal convention flow of air through the hive takes over. That is, when the honey drying operation is stopped by the bees, warmer air within the hive rises to the top and exits therefrom.
To the best of my knowledge, the fact of air flowing through the top opening into the hive, during the honey drying process, has been unobserved and unrecorded previously.
The provision of the upper air inlet opening for the hives gives the following benefits:
1. There is an adequate supply of air for the honey drying process, so that the honey will contain less water--be dryer and sweeter--than honey produced in comparable hives without an upper air inlet.
2. The elimination of clustering of the bees on the front of the hive releases those bees for more productive work, e.g. gathering nectar for the production of more honey.
3. The elimination of clustering on the front of hives reduces the tendency for swarming.
It now appears, therefore, that there are two opposing requirements that the bees have, with respect to air flow through the beehive and the supply of air to the bee hive. On the one hand, the bees wish to make the hive almost airtight by propylizing it, so as to prevent heat loss from the hive during cold weather. On the other hand, the bees require large amounts of air to dry the nectar and to make honey, and this in turns requires that there be an opening at the top of the beehive.
The honey drying ventilator for beehives, of the present invention, satisfies both of those requirements; and particularly, because it is such that air flow through the beehive is permitted from the top to the bottom only during the weather conditions that the bee activity is directed towards honey production. In other words, air flow downwards through the beehive is required only at the time the bees are drying nectar within the hive and making honey--i.e., during the honey season--and only on days when the ambient air temperature is above about 65.degree. F. This requirement is even greater when the temperature is above about 65.degree. F. and the relative humidity is high.
Preferably, any ventilator should be located in the same face of the beehive as the bottom bee entrance. This is in contradistinction to Wallace, which requires two opposed sets of openings in his ventilator spacer, to provide and promote cross flow. Of course, as noted, the ventilation openings of Wallace are always open.
When the ventilator opening of the honey drying ventilator according to the present invention is in the same face of the beehive as the bottom bee entrance, this precludes draft through the bee hive as a consequence of wind. If the wind blows in a direction which is normal to the face of the hive containing the openings, at top and bottom then the pressure against the openings is substantially equal and there is no forced air circulation through the beehive. If the openings are in the other faces, either back or side relative to the face in which the bottom opening is placed, a draft will occur, and air continuously flows through the hive as a consequence of forced air circulation, for so long as the wind continues to blow. Such a draft is not only undesirable, but it could be very detrimental if, for example, a draft of cold air were to kill a brood of unborn bees within the hive.
I have also noticed, as an adjunct to use of the honey drying ventilator for bee hives according to this invention, that it is helpful to reduce the height of the bottom bee entrance in the hive which improves the efficiency of the bees in pumping out drying air from the hive, and lessens the chances for a localized air eddycurrent to establish.
Further, any bee entry holes on the front wall of brood chambers within the hive should be blocked or plugged, because air entering those holes passes down along the brood chamber wall to the bottom bee entrance, without doing any honey drying, and thereby reducing the efficiency because of the required additional air flow pumping action of the bees at the bottom bee entrance to move such air.